A federal grand jury issued a second superseding indictment on Wednesday against a Plano man accused of trying to blow up a natural gas line.

Anson Chi, 35, is now accused of lying in court. He has been in custody since he was critically injured in an explosion in June 2012. Authorities say the self-described political activist tried to place a homemade explosive device on a pipeline in the 3600 block of West Parker Road. It somehow went off, injuring Chi.

Chi recently fired his attorneys and is representing himself at trial, which is currently scheduled for June 30. He claims he was tortured into making a confession while in the hospital.

Three of the counts are identical to the previous indictment: possession of a firearm (destructive device) not registered in the National Firearms Registration and Transfer Record; malicious use of explosive materials; and use or carrying a destructive device during a crime of violence.

The new fourth count accuses Chi of making false declarations before a court. The indictment refers to statements Chi made at a March federal hearing about his legal papers and books being confiscated when he was transferred from the Collin County Jail to the Fannin County Jail. According to the indictment, Chi signed a property release form to have the materials released to his mother.

A federal judge this week also denied Chi's motions to appoint an explosives expert and forensic pathologist for his defense. The judge explained that Chi must identify the specific experts and include their qualifications and rates. But Chi notes that because he is in custody, he doesn't have the ability to find them.